جستجوی مقالات مرتبط با کلیدواژه « biodiversity » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

Various environmental and managerial stresses are severely threatening wetland ecosystems in Iran. The Gavkhouni Wetland, one of the largest and most strategically significant wetlands in the central plateau of Iran, faces numerous challenges. Given its unique ecological importance and the diverse plant habitats surrounding it, studying the vegetation in this area is crucial. Understanding the various conditions of the plants, including dominant families, geographical distribution, biological forms, and conservation status, is essential for any conservation, management, or ecological research activities in this region.

The study area encompasses the upper reaches of the Zayandehrud River in Isfahan Province, covering 50,000 hectares with elevations ranging from 1,470 to 2,533 meters above sea level. This region has an arid climate characterized by saline soils, including solonchaks, marshy areas, and sandy soils. The average annual temperature at Gavkhuni Wetland is 17.6 degrees Celsius, with total annual precipitation measuring 91 millimeters. According to the Ambrothermic curve, the area experiences a prolonged dry period from April to November. Field surveys were conducted using 1:25,000 scale topographic maps from early October to November 2021. During these surveys, plant samples were collected, pressed, dried, and identified at the herbarium of the Natural Resources Department of Isfahan University of Technology, with consultation from experts and reliable scientific sources. This research resulted in a comprehensive list of plant species, detailing their scientific names, families, genera, life forms, geographical distribution, and conservation statuses.

The study identified 100 plant species from 16 families and 65 genera in the region, with 27 species possessing medicinal and industrial properties. The Amaranthaceae family, with 31 species, and the Asteraceae family, with 14 species, collectively constitute 45% of the vegetation cover. Other prominent families include Poaceae with 10 species and Fabaceae with 9 species. In terms of life forms, therophytes dominate at 40%, followed by hemicryptophytes at 23%. Geographically, 71% of the identified species belong to the Irano-Turanian floristic region. Despite the ecological challenges faced by the area, its diverse topography and edaphic factors have fostered significant species diversity.

Gavkhuni Wetland's flora is highly sensitive to climate and management practices. Despite facing severe biological constraints, the region exhibits relatively robust plant diversity. Inadequate management of the Zayandehrud watershed, particularly in Gavkhuni Wetland, has resulted in declining groundwater levels and increased aridity, threatening many plant species with drying, pest infestations, shrub encroachment, and overgrazing. Continued adverse conditions, exacerbated by climate change, pose a significant threat to the region's flora.

The largest part of the biodiversity of terrestrial ecosystems is in pastures and agricultural lands. In terms of biological importance, the Zagros mountain range has the richest and most diverse biodiversity, which faces the dangers of land use change and invasive species. Earthworms, soil ecosystem engineers, have been of great interest in soil physicochemical processes and evolutionary studies. Recent studies indicate the adverse effect of human activities and land use change on the diversity of earthworms. Since the identification of earthworms, using morphological methods is ambiguous; therefore, we need to use genetic methods and molecular markers to separate worms. In this study, we identified taxonomic functional units (OTUs) in earthworms using morphological information and molecular marker COI. Then, we have investigated the effect of agricultural uses on the genetic diversity of earthworms in Central Zagros, Borujerd County using multifactorial statistical analysis. We separated into 13 OTUs belonging to seven genera based on the results of the genealogical tree. The results of the comparison of wheat, alfalfa, sugar beet and clover pastures and farmlands showed that the OTUs of the farmlands all belong to the Lumbricidae family and the OTUs of the pastures, in addition to this family, were in the Megascolecida and Hormogastridae families. In total, we observed four genera of Helodrilus, Aporrectodea, Bimastos and Allolobophora in agricultural lands and six genera of Metaphire, Aporrectodea, Bimastos, Esenia, Allolobophora and Hormogaster in pastures. The results of the ranking analysis of the multifactorial analysis method in land use groups, soil physicochemical characteristics and indicators of abundance and biodiversity of earthworm OTUs with nine factors in 36 variables showed that OTUs C, H and I, all of Aporrectodea rosea species, are the most effective based on multi-factorial analysis in abundance and biodiversity. The biodiversity efficiency index of earthworms of grassland ecosystems was higher than agricultural ecosystems in all cases. Compared to other agricultural ecosystems (wheat, sugar beet and clover), alfalfa cultivation had the highest efficiency index in earthworm biodiversity and the lowest efficiency index was in wheat cultivation. Sugar beet and alfalfa croplands had more OTU diversity compared to clover and wheat croplands. The selection of alfalfa cultivation in crop rotation will increase the biodiversity of earthworms and the stability of agricultural ecosystems. Considering the importance of earthworms in providing ecosystem services and soil quality, it is necessary to conduct more research on the effect of common agricultural ecosystems on the biodiversity of earthworms.

Introduction and Goal:

In recent years, the use of flood spreading systems is one of the most effective ways to control surface water, especially in arid and semi-arid regions which In addition to the reduction of the harmful effects of floods, it results in the reduction of soil erosion, the strengthening ground water tables, the improvement of agricultural lands and the rehabilitation of rangelands vegetation. In flooded rangelands, there is little information about the characteristics of the soil seed bank. This, in turn, has cost and wasted a lot of time. The presence of many species in the seed bank can explain the effects of environmental and management factors in the past. Identification of this resource plays an important role in the protection and restoration of vegetation. In this regard, the aim of the current study is to assess the biological diversity indicators of the existing seed bank due to flood spreading in order to restore and improve the vegetation cover in such rangelands.

In order to investigate the effects of flood spreading on the composition, density, diversity, richness and evenness species of the soil seed bank in two areas with flood spread and without flood spread (Control) in Gareh Bygone Fasa region, seed bank research was carried out for three years from 2020. In June 2020, was done after the preliminary identification of the rangelands of the flood spreading area, the location of two representative areas inside and outside the flood spreading area (Control). Sampling of the soil seed bank in the fall of 2020, before the seeds in the soil began to grow. Inside the representative area (rangeland flooded in 6 strips) and Control (rangeland without flooding), 1 transect of 150 meters was established in the direction perpendicular to the slope of the land. At 10-m intervals along each transect, a 1-m2 plot was randomly selected (total of 15 plots or repetitions). A pit with a diameter of 7 cm and a depth of 0 to 5 and 5 to 10 cm was dug in the four corners and center of each plot. Soils of each depth were combined separately in five points of one square meter plot and considered as a sample for planting in special trays in the greenhouse. The soil seed bank samples were kept in the refrigerator for four months to break the seed dormancy and then transferred to the greenhouse environment for one year for cultivation and by the seedling emergence method, the seeds in the soil which gradually they turned green, were identified and counted.Analyzes related to the seed bank were performed based on the number of germinated seedlings and counted in the greenhouse. The density of species in the soil seed bank was calculated by calculating the total number of seeds of all species per square meter. The diversity, richness and evenness of species were assessed using PAST software. For species richness of the soil seed bank, Margalef and Menhinic indices were used, Shannon-Wiener and Simpson indices were used for diversity, and Hill index was used for evenness. To compare the properties of the soil seed bank (density, richness, diversity and evenness of species) was also used between two representative areas of flooded rangeland and non-flooded rangeland (control) independent t-test and paired t-test were also used to compare between two depths of 0-5 and 5-10 cm. The analysis was conducted via R software, employing one-way analysis of variance and Duncan's method for comparison of means.

The results of the greenhouse studies showed that a total of 5340 seeds germinated in the greenhouse, 3756 seeds germinated in the flood spreading area at a depth of 0-5 cm and 1190 seeds germinated at a depth of 5-10 cm. In the area without flooding (control), 329 seeds grew at a depth of 0-5 cm and 65 seeds grew at a depth of 5-10 cm. In the flood spreading area of Aquifer Management Kowsar Station, in terms of the average density of the seed bank, at a depth of 0-5 cm, a total of 113 seeds per square meter (from 18 plant families and 61 species) sprouted. At a depth of 5-10 cm, a total of 36 seeds per square meter (from 18 plant families and 56 species) germinated. In the control area, in terms of the average seed bank density, at a depth of 0-5 cm, the average of 9.96 seeds per square meter (from 10 plant families and 23 species) germinated. At a depth of 5-10 cm, the average of 1.96 seeds per square meter (from 8 plant families and 15 species) germinated. The average density of sprouted seeds in the soil depth of 0-5 cm was 3.14 times higher than that in the soil depth of 5-10 cm. In the control area, the average density of germinated seeds in the soil depth of 0-5 cm was 5.08 times higher than that of the soil depth of 5-10 cm. The results of variance analysis showed that in terms of biodiversity indices (density, number of species, diversity, and richness species evenness) between the strips of Bisheh Zard 1 and control flood spreading network at the depth of 0-5 and 5-10 cm of the bank, there is a significant difference between soil seeds at the level of 1% and 5%. The results of the t-test showed that in terms of biodiversity indices between the depths of 0-5 and 5-10 cm of the soil seed bank both in the flood spreading area and in the non-flooding area (control) there is a significant difference in there are 1% and 5% levels.

Conclusion and Suggestions:

In general, it can be concluded that the implementation of flood spreading operations in the studied area has created a special ecosystem that has improved the environmental conditions such as sufficient humidity and suitable organic matter in the area. Also, it has a significant effect on increasing the density and diversity, richness and evenness of the soil seed bank species, as well as the species composition. Therefore, the potential of the existing seed bank can be used to rehabilitation this area and similar areas. In general, the results of this research showed that the soil seed bank of this region had a positive response to the implementation of the flood spreading operation, so that the highest density, diversity, richness and evenness of the soil seed stock was observed in the flood spreading area. It is suggested to carry out projects on the effects of flood spreading on biodiversity indices in forestry plots with different species of Eucalyptus, Acacia, as well as shrub planting plots with Atriplex species, as well as a control plot be compared in Gareh Bygone, Fasa. This research's findings can be used in preserving plant diversity, preserving genetic reserves, and revitalizing and managing vegetation in the region.

Protected areas are parts of the land that are selected and managed for effective in situ biodiversity conservation, among other important ecosystems features. With an efficient network of protected areas located in the right places to represent all ecosystems, ecological resource management can better be achieved. Gap analysis provides a tool for assessing the degree to which biodiversity is represented in conservation areas that help land managers and policy makers when they need to make appropriate decisions. In this study, the representativeness of the national parks system as part of Iran’s protected areas network, for terrestrial ecosystems was investigated. For this purpose, suitable criteria and indicators for national parks selection were identified and mapped. We developed a decision-making algorithm for assessing the representativeness of the national parks based on the set goals mentioned above. Using the algorithm, the indicators layer was overlaid with the ecosystems layer and national parks and the national parks coverage of ecosystem patches was evaluated and coded. Having calculated the coverage of the ecosystems, three scenarios were defined and their realization was assessed in each ecosystem, hence showing the lack of ecosystems’ protection. The results showed that the three scenarios have only been realized in two ecosystems of Cold & Arid Bare Mountains and Arid Scrubland & Halophytes, and in other ecosystems, the level of representativeness is not sufficient. Based on this, the area required to complete the system of national parks in terrestrial ecosystems was calculated as around 2000000 hectares. The results of this study can be a guide for land protection planners to revise the system of terrestrial national parks in Iran.

Biodiversity provides various ecosystem services to human societies and addresses human needs, but human interventions have caused biodiversity loss and reduced ecosystem services. The designation of protected areas is a strategy to manage environmental crises and biodiversity loss, but these areas are under threat. This research analyzes the factors affecting biodiversity loss in protected areas using a quantitative methodology (descriptive-correlational). Data were collected through structured interviews, using a questionnaire, with 250 out of 5095 rural households of the local communities of the Sorkhabad Protected Area of the Zanjan Province. The sample size was calculated using the Cochran sampling formula and was randomly selected through the multi-stage sampling technique. The questionnaire was developed by the research team and its questions’ content and face validities were assessed and verified by an expert panel in this field. The reliability of the research instrument was also confirmed by conducting a pilot study and applying Cronbach’s alpha test. The results showed that the biodiversity loss is determined by the variables of local community participation, interventions by external organizations, human drivers related to local communities, the livelihood, motivation, and knowledge of local communities, attitudes towards biodiversity conservation, knowledge about biodiversity degradation, knowledge about biodiversity challenges, and knowledge about ecosystem services, which explained 68 percent of biodiversity loss variance. Therefore, it is necessary for decision-makers and policy-makers to pay attention to relevant and effective factors in reducing the loss of biodiversity in order to conserve and restore ecosystems and species in protected areas.

The sudden increase in population growth, followed by the restriction and scarcity of the world's supply of freshwater resources, has created new conditions for countries in the arid and semi-arid belts. To conserve, enhance and make the best use of these valuable resources, several projects have been implemented, including irrigation and drainage, flood control and dam construction. Meanwhile, dams are a very important tool to manage the river water for socio-economic development and also to improve the deteriorated ecological status of the river system and its services. Depending on place and time, dams play both negative and positive roles in environmental flows, with significant environmental costs. According to the results of the documents and reports, the construction of the dam has brought about environmental changes from various aspects of invasion and increase in invasive species to improving access to spawning habitats for migratory fish. The challenge for managers and scientists today is to better understand and manage the consequences of dam decommissioning. For this reason, the purpose of this study is to present the approaches of removing the dam on ecological changes. The results of this research can provide stakeholders in the responsible departments with valuable information about the changes in the behavior of dams on the environmental properties.

 Considered two important contributing factors in reducing biodiversity in rangelands, drought, and grazing influence the performance of natural ecosystems. Moreover, plant communities respond variously to drought periods under different management conditions. However, while many studies have so far been conducted on the response of plant communities to drought, it is not clear whether the ecosystems are more resistant or more vulnerable to drought. Therefore, this study sought to examine the impact of grazing intensity (including lenient, moderate, and heavy grazing) on vegetation characteristics (such as canopy cover, forage production, and species diversity) of semi-desert ecosystems of South Khorasan province under normal, wet, and drought conditions.

 This study attempted to investigate the structural properties of Salsola richteri and Artemisia sieberi- Zygophyllum eurypterum communities in the grazing and enclosed rangelands under short-term wet and drought conditions. To this end, canopy cover, density, forage production, and the richness and diversity of species were measured according to the Guidelines set by the Iranian National Program for Monitoring Rangeland Quality. Moreover, the species abundance index was used to assess plant diversity indices. Accordingly, after recording the plant density values and converting them to abundance ones, the species richness, dominance, diversity, and evenness were calculated using the adiv package. On the other hand, the Standard Precipitation Index (SPI) was used to assess the drought. Finally, the statistical analysis of the data was performed using the Wilcoxon signed-rank test and permutation test. 

 The results of the SPI analysis indicated that the Salsola richteri community experienced normal and very dry years in 2019-2020 and 2020-2021, whose SPI value was found to be 0.097 and 1.6, respectively. As for the Artemisia sieberi- Zygophyllum eurypterum community, the years 2019-2020 and 2020-2021 fell under relatively humid and normal classes, respectively, with their SPI values being 1.14 and -0.70, respectively. Moreover, it was found that annual species were eliminated by drought, especially Salsola richteri and Ammothamnus lehmanii which were affected the most among other species. Accordingly, the production of Salsola richteri was reduced from 800 kg/ha to 60 kg/ha and Ammothamnus lehmanii was completely dried. However, the results showed that canopy cover and density of perennial species were not significantly influenced by drought (p≥0.05). For instance, Ammodendrom persicum and Stipagrostis pennata, which had the highest density in this region, were less affected by drought. On the other hand, in the enclosed rangeland, the species diversity of the Salasola community was higher in the normal year (1-D = 0.15) than in the dry one (1-D = 0.105). It was also found that in the Artemisia sieberi- Zygophyllum eurypterum community, decreased precipitation rate was more influential in reducing forage production than other vegetation properties. In this regard, the production of all plant species was approximately zero in the normal year, with the grazing capacity being impossible to determine. 

 As found by the current study, drought exerted a significantly negative influence on the density, richness, and diversity of species in the Salsola community, with species dominance being greater in the dry year than the normal one. Therefore, it appears that compared to the Artemisia sieberi- Zygophyllum eurypterumcommunity, the Salsola community enjoys a higher species diversity.
On the other hand, 2020 and 2021 were determined as the wet and the normal years based on SPI, respectively. However, although 2021 was identified as a normal year, the increased temperature and decreased precipitation rate during the sampling period so negatively affected the vegetation that the year was practically considered a dry year. Moreover, the comparison of the wet and normal years suggested that the density, canopy cover percentage and forage production of annual species had turned to zero throughout the normal year. However, the Artemisia sieberi- Zygophyllum eurypterum community experienced much worse conditions than the Salsola community, where the species richness in both grazing and enclosed rangelands decreased from 25 species to 4 and 7 species, respectively. It was also found that all annuals and herbaceous species had been eliminated from the region and only perennial plants and shrubs had survived. This study examined biodiversity as one of the most important characteristics of plant communities that could be affected by drought, as biodiversity is believed to be involved in improving the performance of natural ecosystems. Furthermore, biodiversity can protect an ecosystem's performance against severe weather events. Considering the response of plant species to drought, Ammodendrom persicum is recommended as a drought-resistant plant to be planted in areas that are subject to the programs dedicated to the revival of dry and desert regions. On the other hand, being generally defined in terms of different aspects, drought is classified into various types, including meteorological, hydrological, agricultural, economic, and social. In this regard, ecological drought is also recommended to be added to such a classification.

Considering the importance of the forests of North Zagros in terms of conservation, economic-social and regeneration, this research aims to identify the composition and diversity of herbaceous species in different oak types located in Armardeh forests in Baneh city and the relationship between the herbaceous cover with edaphic conditions. Forest types were identified with field inspection. In each type, 5 samples of 500 square meters were randomly collected to collect trees and 5 soil samples were taken from each types to a depth of 10 cm. Also, a small sample of one square meter was randomly used for herbaceous species. The biological form of the species was obtained using the Raunkiaer method, the chorotypes according to were obtained to Zohary method, and the biological diversity was obtained using plant diversity indices, then the relationship and ordination of the vegetation with edaphic variables were investigated with detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA). The results showed that Asteraceae, Fabaceae and Poaceae families have the highest number of plant species respectively. Trophies and hemicryptophytes had the highest percentages, respectively, and the most important chorotypes of the region were the vegetative elements of (Iranian-Turan). The results of variance analysis, Pearson's correlation and vegetation ordination showed that the separation of vegetation types, species distribution in North Zagros was mainly influenced by soil texture, sodium, organic matter, potassium and phosphorus. According to the findings of this research, it can be acknowledged that due to the widespread of Zagros forests, attention to forest types and soil can represent the changes in the vegetation cover and be considered in the management of these forests.

Special areas for conservation are the natural sites with valuable natural components which are managed through relevant organizations. Suggesting and establishing these areas, along with the other IUCN common areas designated for ecosystem conservation and protection will strengthen the conservation of ecosystems and their functions. The status of subjects in the Iranian statute law regarding forests and rangelands is often ambiguous or neglected and needs to be updated. In this regard, by using comparative law, the strengths and weaknesses of domestic law can be examined and the necessary amendments can be proposed. This research is a comparative study of forest and rangeland statutes in Iran, France, and South Africa regarding the allocation of areas with special management regimes, outside the common area for protection established by the environmental laws. This comparative study has been conducted in five steps including 1- defining research scopes, 2- Describing, 3- Comparing, 4- Explaining, and 5- Evaluating and proposing suggestions. The results showed that special areas for conservation in Natural Resources Organization (NRO) territory include 1- Natural and biological reserves, 2- Biological heritage and biodiversity, and 3- Sensitive and fragile ecosystems, mainly managed according to conservation measurements. It seems that South Africa has the most suitable legal system in this regard by granting special permissions to the Minister to establish special conservation zones, using scientific advice in determining the minimum area for conservation, considering suggestions and objections, as well as criteria, indicators, and standards for biodiversity conservation. We provide suggestions to amend and update domestic law on this subject and establish special areas for the conservation of NRO management regimes.

Livestock grazing management is one of the main manifestations of integrated watershed management. Lack of awareness of the effects of livestock grazing on biodiversity makes sustainable watershed management impossible. Therefore, awareness of the variation in plant diversity and composition under natural disturbances such as livestock grazing is important for optimal ecosystem management. This study aims to investigate the effects of different grazing intensity (low, moderate, and high) on spatial diversity components (α-diversity, β-diversity and γ-diversity), turnover and nestedness components of β-diversity and species composition in semi-steppe Broujen rangelands in Chaharmahal and Bakhtiari Province. Vegetation sampling was conducted based on a random-systematic sampling design using 60 plots of 2*2m in three grazing intensities including low, moderate and high. Statistical analysis was performed in R software using “vegan” and “betapart” packages. The results showed that an increase in grazing intensity could significantly (P-value < 0.01) decrease α-, β- and γ-diversity indices, which, in low grazing intensity, were 11.77, 7.22, and 19, respectively, while in high grazing intensity they were 3.44, 3.55, and 7, respectively. In addition, an increase in grazing intensity could significantly (P-value < 0.05) increase the turnover component of β-diversity due to species replacement, while there was no significant effect for nestedness components of β-diversity. The NMDS analysis results showed that different animal grazing could drive a significant deviation in plant community composition. The results of this study suggest that the light grazing intensity could be used as a suitable management tool in order to maintain and improve plant biodiversity.

Allelopathy refers to the plants’ mutual biochemical effects. Despite their significant role in improving and restoring Iranian rangelands, the plants’ allelopathic effects on each other have often been neglected in rangeland seeding. Scholars argue that in stressful conditions of the arid areas caused by low precipitation, the effects of metabolic chemicals secreted by allelochemical-full plants on adjacent species increase and allelopathy plays a more important role in creating plant communities of natural habitats. Considering the fact that seeding and sowing are considered as acceptable methods of improving and restoring rangelands in potential areas for increasing vegetation in semi-steppe and steppe areas, and that the allelopathic effects of dominant woody species are among main causes of seeding and sowing failure in some regions, this study sought to investigate the allelopathic performance of some woody species including Amygdalus scoparia, Daphne mezereum, and Ebenus stellata on seed germination of their understories species. Therefore, this effect should be identified for the improvement of rangelands in order to provide suitable shrub species for improvement and restoration.

this laboratory study investigated the effect of aqueous extracts of Amygdalus scoparia, Daphne mezerum, and Ebenus stellata on their understories seed germination, using total random sampling with three replications. To this end, some fifteen samples were randomly collected from habitats of Amygdalus scoparia, Daphne mezerum, and Ebenus stellate in the growing season of dominant rangeland plants. The collected leaf samples were dried for 48 hours in oven at 80°C temperature for extraction (aqueous extract). Then the extraction was performed in 1:3 (w/v) ratio on all milled samples. Experimental treatments included aqueous extracts of woody leaves with 1% concentration and distilled water (control). Moreover, distilled water was used as a solvent for performing the extraction in the laboratory (24 h soaking time) which was done in cold water to simulate normal conditions. To increase the contact of the samples’ particles with the solvent, a shaker device was used. To separate the suspended solids from the solvent, cold centrifuges were used at a temperature below 5°C. Then, three petri dishes with a diameter of 120mm and a thickness of 15mm (each container 1replicate) were used for each treatment in which twenty seeds had been put. Having added the solutions, the petri dishes were tapped and placed in a growth chamber under dark conditions at a temperature of 20-25°C and 50% humidity. The seed with two cotyledons was considered as the germinated seed. The collected data were analyzed by SPSS software. Having performed a two-way variance analysis, Duncanchr('39')s test was carried out to compare the means of the significant treatments. Moreover, the Excel software was used for drawing the intended graphs.

this study investigated the effect of aqueous extracts of three woody species and the control treatment on germination rate of understories plants at 5% probability level. The results indicated that there was a significant difference (P <0.05) between the mean of different species’ germination in most cases. It was also found that the aqueous extract of Amygdalus scoparia had decreasing effect on Medicago radiate, Alyssum sp. Ziziphora tenuior L, the aqueous extracts of Daphne and mezerum Ebenus stellata reduced germination of Astragalus podolobus Boiss, Alyssum sp., Bromus tectorum, and Amygdalus lycioides, respectively. The results also showed that the aqueous extract of Amygdalus scoparia had the greatest effect on the germination of the species of Sterigmostemum longistylum Boiss, Clypeola aspera L.,Lolium perenneL. Moreover, the aqueous extract of Daphne mezerum increased germination of Amygdalus lycioides and Ziziphora tenuior L., while the aqueous extract of Ebenus stellata  only increased Astragalus podolobus Boiss germination. Furthermore, it was revealed that the aqueous extracts of Amygdalus scoparia, Daphne mezerum, and Ebenus stellata had no significant effect on germination of rangeland species (Bromus tectorum, Astragalus podolobus Boiss,Amygdalus lycioide), seeds of Sterigmostemum longistylum Boiss, Medicago radiate, Clypeola aspera L., Lolium perenneL., Bromus tectorum, Alyssum sp), and seeds of Sterigmostemum longistylum Boiss, Lolium perenneL., Medicago radiate Clypeola aspera L., respectively.

according to the study’s findings, the aqueous extracts of the three woody species and the control treatment had different inhibitory effects on germination and seedling growth of the understory species. However, it could generally be said that the understory species experienced the highest germination rate under the control treatment. In some cases, the aqueous extract was found to have decreased the germination rate, which could be due to the Artmisian active biologic properties as a toxic Sesquiterpene lactone and has a n inhibitory effect. As the woody species investigated in this study were mainly found in mountainous areas with sandy-loamy texture, it can be argued that in areas where these woody species are dominant, the leaching of understories may reduce their inhibitory effects in comparison with those of the understories’ ones. Therefore, woody species do not have any allelopathic effect at low concentrations on germination of their understory rangeland seeds, and that was why they were abundantly found in the growing season of the rangeland plants under study. Some researchers argue that geographic aspects could also contribute in decreasing the species’ allelopathic effects on seed germination, with the northern aspects having less inhibitory effects than the other directions. soil temperature, and the amount and intensity of light and intensity may cause meso-climatic changes. Therefore, as the germination stage is a critical stage in plants growth and early growth stages play a very effective role in plants establishment, choosing the appropriate cultivar type can guarantee the success of germination and seedling establishment under different environmental conditions. Thus, in restoration projects compatible species should be used. Generally, it could be argued that plant species may exert different effects on vegetative characteristics of habitats in arid and semi-arid climates. So, knowing the type and extent of such effects is necessary for managing, improving, and developing the rangelands.

The functional properties of a plant can link the plant physiology with community and ecosystem processes. Thus it provides an appropriate tool for investigation of environmental changes and biodiversity. For this purpose, Zeiar rangeland of Damavand Mountain were selected as the 6000ha study area​​. A stratified-random sampling method was used for the sampling of vegetation and soil. Topographic variables including slope, height, and slope direction were used to classify the study area and making a land mapping unit map. In each unit, 10 plots of 1 m 2 were randomly established and list of the plant within the plot were. In addition plants numbers, and functional characteristics including leaf specific area, leaf dry matter, plant height and seed weight were measured and put it in the list. Three soil samples were taken from 0-30 cm depth in each sampling unit. Soil variables including nitrogen, phosphorus, potassium and organic carbon content were measured in the laboratory. The climatic variables taken into account were annual relative humidity, mean annual temperature and mean annual rainfall. Effect of environmental factors on functional properties were evaluated using RLQ and Q-corner methods in ade4 package of R software. The results showed that the first RLQ axis showed 84% environmental variability and 87% variance of features. The correlation coefficient along the RLQ axes were 0.62 and 71% which is the best correlation. Also, the results of Fourth-corner test showed that leaf specific area was positively and significantly correlated with soil organic carbon, phosphorus and nitrogen. Leaf dry matter and seed weight were negatively correlated with soil organic carbon. Combining the two methods could clearly improve the relationships between RLQ axes and environment-trait variables. Thus usage of the methods is suggested fot the same studies.

Pteridium aquilinum is known as an invasive species  in different ecosystems of the world. The spread of this species is increasing in the north of Iran particularly outside of forest ecosystems. In this study, the amount and composition of soil seed banks in the dense pathes of  Pteridium were investigated in summer rangelands of  Bandpay in the south of Babol city in Mazandaran province, Iran. Soil seed bank sampling was done before the growing season in five vegetation types invaded by Pteridium including beech forest, shrubland dominated by Crataegus meyeri, shrubland dominated by Berberis vulgaris-Crataegus meyeri, rangeland and an uninvaded rangelan. Soil samples were kept in glasshouse and seedlings were identified and counted. The results showed that the mean density of soil seed bank  in invaded rangeland was about 2900 seeds/m2 and this was significantly graeter than that in other invaded vegetation types and uninvaded rangeland. The dominant species in the soil seed bank were Spergularia bocconi, Stellaria media, Plantago lanceolata,  Trifolium sp., and Poa annua. A total of 24 species were restricted to the soil seed bank of invaded sites. Despite the impact of Pteridium invasion on seed bank composition and size, the soil seed bank diversity and richness was not significantly different between invaded and uninvaded sites. A low seed density of grasses and palatable species were found in the soil seed bank (about 6.5% of total seed bank), therefore it is not possible to rely on soil seed bank for restoration of thses invaded sites following Pteridium control.

Evaluations of the threatening factors to wetlands are necessary to sustain these ecosystems and improving them. The main goal was to identify and prioritize the factors threatening the Choghakhor wetland watershed. This research has been consisted of a cohort of 315 participants in an exploratory mixed method. Data analysis was performed by One-Sample T-Test and non-parametric Friedman Test. Factors threatening were evaluated and prioritized in four areas including: natural disasters, and biological, cultural and socio-economic threats. Living in the area, threats to this wetland are in an undesirable and unacceptable state. Likewise, the greatest impact is associated with the cultural threats and the biological threats obtaining the lowest priorities. In the field of cultural threats, a lack of coordination between government agencies in matters relating to the wetland with a mean score of 2.35. In the field of socio-economic threats, inter-basin water transfer from the Mount Sabzkouh to Choghakhor wetland with a mean score of 11.69; in terms of natural disasters, climate change and the melting of mountain glaciers with a mean score of 6.04; and, in the field of biological disasters, unauthorized grazing (over the production capacity of rangelands) have been recognized as the first priorities with a mean score of 2.29. As the final statements, it appears that cultural, followed by socio-economic threats are the most significant factors contributing to the destruction of this ecosystem. In the perspective of the participants, cultural and educational-based management could be the ideal solution for the current condition of the wetland.

Sustainability as a turning point in the reciprocal and harmonious relationship between society and nature has made the environment as a third dimension to play the role, alongside with economics and society. One of the important problems for scientists at present is to identify the suitable indicators to make decisions and to study the relationships and interactions between society and nature. Material and Energy Flow Accounting (MEFA) based on socioeconomic metabolism approach provides an important analytical framework for the interaction of society and nature. This research aimed on evaluating the human disturbance using Human Appropriation of Net Primary Production (HANPP) and its methodology as well as the effect of landscape structure on energy flows which effects landscape function. HANPP as one of the MEFA indicators has gotten more attention of various researchers due to its function on a variety of global to local scales. The results of this study showed that Qazvin province has 90.658 million GJ Net Primary Production potential (NPP0) and from this potential, the real production is only 34.552 million GJ NPPact. As a matter of fact, only 9.446 million GJ remain in nature as NPPuh to meet the biodiversity needs from NPPact in Qazvin province, and the rest are harvested by humans and entered in the social system as NPPh. As a result, just 10.42% of Qazvin's potential net primary production is spent on biodiversity and the rest is either destroyed or consumed by humans. The results of this study can be used to gain a systematic insight into landscape and socio-ecological system analysis in order to preserve biodiversity needs, along with human needs.

The ecological model of productivity-species richness relationships states that maximum species diversity occurs when species production is moderate, and there is a humped-back pattern between production as ecosystem energy variable and species richness. The discovery of this relationship leads to an understanding of the processes of biodiversity formation in ecosystems. To test this model, species production and richness were measured in the semi-steppe ecosystem of Gharebough in the Anguaran wildlife refuge in Zanjan province. Correlation and linear and nonlinear regression analysis were used to examine the relationship between species richness as a dependent variable and productivity as an independent variable. A total of 41 plant species were identified in 30 plots. The average species richness per plot per square meter was calculated as nine species. The relative production percentages were 15% for shrubs, 16% for forbs, and 69% for grasses. The highest percentage of presence in the plots was allocated to Stipa lessingiana, Poa bulbosa, Astragalus stevenianus, and Bromus tomentellus. The total production of the species was calculated to be 83 g/m2. Shrub production and forbs showed a significant linear regression relationship with species richness. Also, the shrub production had a significant nonlinear regression relationship with species richness, showing a humped-back pattern. The findings of this study showed that increasing production increases species richness and according to the values of the coefficient of explanation of regression relations (R2), in addition to the production factor, other important factors play a role in species richness. Therefore, this hypothesis cannot be confirmed on a local scale.

Invasive species are the major threats to natural ecosystems worldwide. Pteridium aquilinum has the widest distribution of any pteridophyta in the world. This study aimed at investigating the impact of Pteridium aquilinum invasion on species composition, richness and diversity, and forage production in summer rangelands of Bandpay Babol, Mazandaran province, Iran. Vegetation was sampled in four invaded vegetation types including Fagus orientalist forest, Crataegus shrubland, Crataegus+Berberis shrubland, and rangeland. Also, vegetation sampling was done in surrounding uninvaded rangelands. The cover of species was estimated in 1 m2 plot for herbaceous and 25 m2 for shrubs. In all plots, the cover of P. aquilinum was estimated and then all fronds were cut at ground level, counted and frond length was measured. The forage of palatable species was measured by clipping and weighing. Findings showed different species composition among invaded and uninvaded areas. A total of 25 species were found only in invaded areas whereas only 11 species were detected in surrounding uninvaded rangelands. Cover, density and height of P. aquilinum fronds significantly influenced the species composition. Annuals significantly decreased by Pteridium aquilinum invasion. Except for Crataegus+Berberis shrubland, in other invaded areas the forage production was not significantly different from that in surrounding uninvaded rangeland. There was a reduction of desirable rangeland species due to P. aquilinum invasion. Also, we found that species richness significantly increased when invaded by Pteridium, while the diversity significantly decreased. The current understory floristic composition showed a low potential to support future restoration after P. aquilinum control. This result emphasizes the need for adding the seeds of desirable species